Chapter 2. Networking Primer

This chapter discusses the general concepts and features of network technologies pertinent to routers from companies like Juniper Networks. If you have sufficient knowledge of networking basics, you can probably either skip this chapter or just skim unfamiliar sections. This chapter will give you the fundamental knowledge needed in Part III to properly configure interfaces on Juniper Networks routers. A proper in-depth discussion of networking technologies is beyond the scope of this book. For more information regarding many of these technologies, please read the bibliography at the end of this chapter and the recommended-reading list from Chapter 1.

Standards form the basis for all network interoperability. If standards are maintained , then different vendors ' equipment should work together seamlessly (at least in theory). A quick review of the open systems interconnection, or OSI, model and the portions of it we are concerned with will assist in understanding the different functional parts of networking. This fundamental knowledge of layered networking is important for design and configuration, but more importantly for troubleshooting. This discussion is followed by an explanation of encapsulation using the analogy of a mailed letter, which explains the method that keeps functional areas from affecting one another.

The rest of this chapter covers transmission technologies. Basic technologies, such as Ethernet, packet-switched networks, ATM, SONET, and others, will be discussed as the technologies that carry IP. The last section discusses IP, how it is used, as well as identifying a range of IP addresses with a subnet mask and how to manipulate that mask for use in routing.